In CDMA2000 radio access networks (RANs), such as (Third Generation Partnership Project 2 (3GPP2) 3G1x, 1xEV-DO, and 1xEV-DV, packets targeted for mobiles that are sent from the packet data network may be dropped or lost when certain events occur in the RAN. These events include: hard handoffs, Voice Precedence Over Packet (VPOP) situations, 1xEV-DO-A cross paging circuit notifications, mobile paging failures, and buffer overflows in the RAN.
A packet data hard handoff can take several seconds to complete. Inter-PCF (packet control function) hard handoffs may result in an intra-PDSN (packet data serving node) or inter-PDSN hard handoff. Intra-PDSN hard handoffs result in the target PCF connecting back to the source PDSN supporting the packet data when the target PCF has connectivity to the source PDSN. Inter-PDSN handoffs result in a new PDSN being assigned to the mobile's packet data session when the PCF doesn't have connectivity to the source PDSN or the source PDSN is busy. The network may initiate a ‘fast handoff’ when an inter-PDSN hard handoff is required allowing the mobile to delay PPP reconnection/MIP procedures until the packet data session goes dormant. Regardless what type of hard handoff occurs, data targeting the mobile is dropped at the source PCF until the mobile establishes a connection with the target PDSN.
In the case of VPOP and 1xEV-DO-A cross paging circuit notifications, the mobile's active packet data session is transitioned to the dormant state allowing the network to terminate a circuit voice call to a hybrid 1xEV-DO mobile. However, the PDSN continues delivering data for the mobile to the RAN even though the packets can no longer be delivered to the mobile. Furthermore, the RAN may try to re-initiate the packet data session with the mobile as packets destined for the mobile arrive from the IP network.
When the network tries to initiate a packet session (e.g., a packet data call reactivation or a network initiated packet data session), paging may be involved. If the mobile fails to respond to the page, packet data accumulates, potentially flooding the PCF and/or BS buffers. Even without a paging failure, RAN buffers may overflow for reasons such as a poor RF conditions. 3GPP2 standards support a simple Xon/Xoff flow control procedure between a PCF and PDSN. The PCF may request a PDSN to stop and start the transmission of packets to the RAN. However, in the current art, the flow control signaling does not prevent the loss of packets altogether. Internet Engineering Task Force (IETF) RFC 793, which defines the transmission control protocol (TCP), also provides flow control services between data connection termination points, but in TCP lost data is interpreted as congestion and an exponential reduction of data throughput can thereby result. This, of course, further degrades packet data performance. Therefore, a need exists for an apparatus and method of more effectively managing packet data loss in wireless communication systems.